This invention relates generally to apparatus and methods for cleaning chambers and more particularly to apparatus and methods for cleaning slag and refractory material from the interior surfaces of a coal fed cyclone burner attached to a boiler.
Coal-fired boilers are commonly used by industry. For example, utility companies use coal-fired boilers to heat water for generating steam which drives electric generators. Pulverized coal is fed into one such boiler through a cyclone burner which receives the pulverized coal from a feeder apparatus connected to the inlet of the cyclone burner. Initial burning occurs inside the cyclone burner ("cyclone") with further burning occurring in the boiler.
Burning of the coal creates iron slag deposits (sometimes as much as two to three feet thick) on the interior walls of the cyclone. Although some amount of slag is known to assist the combustion, too much is detrimental. Therefore, the inside surfaces of the cyclone need to be cleaned periodically to reduce the deposits to the desired level or thickness. Also, refractory materials may be present on the inside surfaces of the boiler which need to be removed or cleaned from the inside surfaces to allow inspection and ultrasonic testing of the boiler tubes.
Past cleaning techniques have been labor intensive and even the semi-automated cyclone cleaning apparatus have required an operator to enter the cyclone and rearrange or replace high pressure fluid nozzles in order to clean the various inside surfaces of the cyclone. Such a semi-automated apparatus is described in U.S. Pat. No. 4,603,661, which is incorporated herein by reference thereto.
Therefore, there is a need for a chamber, cyclone, or boiler cleaning apparatus and method which can clean the cyclone more quickly, while reducing attendant operator time. There is also a need for a more precise technique of cleaning to ensure consistent cleaning jobs from one cyclone to the next regardless of the construction differences between the cyclones. It is also desirable to have an apparatus and method by which the cyclones can be cleaned more economically.